Disc cartridge

ABSTRACT

A main cartridge body unit reduced in size and thickness. To this end, the main cartridge body unit includes a disc-shaped recording medium  5,  a main cartridge body unit  6  including an upper plate  21  and a lower plate  22,  both of a metal material, forming a plate pair, and an intermediate frame  23,  recording and/or reproducing apertures  24, 25  formed in the main cartridge body unit  6  for exposing a portion of a recording area of the disc-shaped recording medium  5  to outside across the inner and outer rims of the disc-shaped recording medium, and a shutter member  61  provided for linear movement within the inside of the main cartridge body unit  6  for opening/closing the recording and/or reproducing aperture. The intermediate frame  23  is sandwiched between the upper and lower plates  21, 22.  The disc-shaped recording medium is housed in the main cartridge body unit  6.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a disc cartridge having a disc-shapedrecording medium, such as a magnetic disc, accommodated therein.

2. Description of Related Art

There has so far been known a disc cartridge having a flexible magneticdisc with a diameter of, for example, 3.5 inch, accommodated therein asa disc-shaped recording medium. This disc cartridge has a main cartridgebody portion including a set of shells, that is an upper shell and alower shell, combined together. These upper and lower shells are formedof a resin material, and are provided with recording and/or reproducingapertures for exposing a portion of the flexible magnetic disc tooutside across its inner and outer rims. On the main cartridge bodyportion is mounted a shutter member for opening/closing the recordingand/or reproducing apertures.

In the conventional disc cartridge of the above-described type, ashutter member is moved on loading the disc cartridge in a recordingand/or reproducing apparatus so that its recording and/or reproducingaperture is opened. As the flexible magnetic disc is run in rotation,the information is recorded and/or reproduced by a magnetic headintruded through the recording and/or reproducing aperture.

Recently, in a portable electronic equipment, such as a portablecomputer or a digital still camera, a demand is raised for a recordingand/or reproducing apparatus that is able to handle the information of alarger volume, and for a information recording medium used for thisrecording and/or reproducing apparatus.

As for an information recording medium, used for this sort of therecording and/or reproducing apparatus, it is proposed to reduce thesize or thickness of a disc cartridge having the flexible magnetic dischoused therein.

Meanwhile, the upper and lower shells may be formed of a metallicmaterial to reduce the thickness and hence the size of the maincartridge body unit.

However, as the disc cartridge is reduced in size and thickness, therecording and/or reproducing apparatus, on which is loaded the disccartridge, is also reduced in size and thickness. Thus, with thisrecording and/or reproducing apparatus, the cartridge inserting/ejectingopening, through which the disc cartridge is inserted and ejected, is ofan extremely small size, with the result that a gap between the outerperiphery of the disc cartridge and the inner periphery of the cartridgeinserting/ejecting opening (play) is of an extremely small value. Also,in this recording and/or reproducing apparatus, there is provided a dooradapted for being rotated to open/close the cartridge inserting/ejectingopening to prevent intrusion of contaminants through the cartridgeinserting/ejecting opening. When the disc cartridge is inserted into therecording and/or reproducing apparatus, this door slides on the majorsurface of the main cartridge body unit so as to be rotated towards theinside of the apparatus.

That is, the disc cartridge, reduced in size and thickness, has adrawback that it abuts on the cartridge inserting/ejecting opening wheninserted into or ejected from the recording and/or reproducingapparatus, or the door sliding on the major surface of the maincartridge body unit destructs the shutter member arranged outside themain cartridge body unit when the disc cartridge is ejected from theapparatus.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a disccartridge in which a shutter member may be positively prevented frombeing destroyed and in which the main cartridge body unit can be reducedin size and thickness.

For accomplishing this object, the present invention provides a disccartridge including a disc-shaped recording medium, a main cartridgebody unit including an upper plate and a lower plate, both of a metalmaterial, forming a plate pair, and an intermediate frame, sandwichedbetween the upper and lower plates, and an intermediate frame, recordingand/or reproducing apertures formed in the main cartridge body unit forexposing a portion of a recording area of the disc-shaped recordingmedium to outside across the inner and outer rims of the disc-shapedrecording medium, and a shutter member provided for linear movementwithin the inside of the main cartridge body unit for opening/closingthe recording and/or reproducing aperture. The intermediate frame issandwiched between the upper and lower plates. The disc-shaped recordingmedium is housed in the main cartridge body unit.

With the present disc cartridge, in which the shutter member is providedinwardly of the main cartridge body unit, it is possible to prevent loadapplication from to the shutter member from outwardly of the maincartridge body unit.

With the present disc cartridge, it is also possible to preventdestruction of the shutter member and to reduce the thickness and sizeof the main cartridge body unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a disc cartridge according to thepresent invention.

FIG. 2 is an exploded perspective view showing the disc cartridge.

FIG. 3 is a cross-sectional view of a flexible magnetic disc of FIG. 1,taken along line A—A of FIG. 1.

FIG. 4 is a plan view showing an upper plate.

FIG. 5 is a plan view showing a lower plate.

FIG. 6 is a side view of the disc cartridge.

FIG. 7 is a plan view showing an intermediate plate.

FIG. 8 is a cross-sectional of the intermediate frame of FIG. 1, takenalong line B—B in FIG. 1.

FIG. 9 is a cross-sectional view for illustrating essential portions ofthe intermediate frame.

FIG. 10 is a plan view showing, from the side of the upper plate, astate in which the recording and/or reproducing aperture of the disccartridge is closed.

FIG. 11 is a plan view showing, from the side of the lower plate, astate in which the recording and/or reproducing aperture of the disccartridge is closed.

FIG. 12 is a side view showing, from the front end side of the maincartridge body unit, a state in which the recording and/or reproducingaperture of the disc cartridge is closed.

FIG. 13 is a plan view showing, from the side of the upper plate, astate in which the recording and/or reproducing aperture of the disccartridge is opened.

FIG. 14 is a plan view showing, from the side of the lower plate, astate in which the recording and/or reproducing aperture of the disccartridge is opened.

FIG. 15 is a side view showing, from the front end side of the maincartridge body unit, a state in which the recording and/or reproducingaperture of the disc cartridge is opened.

FIG. 16 is a cross-sectional view of a shutter member of FIG. 10, takenalong line C—C in FIG. 10.

FIG. 17 is a cross-sectional view of a shutter member of FIG. 10, takenalong line D—D in FIG. 10.

FIG. 18 is a plan view showing upper and lower liner sheets.

FIG. 19 is a cross-sectional view, taken along line B—B, forillustrating the state in which the flexible magnetic disc has beenmoved towards the lower plate.

FIG. 20 is a cross-sectional view, taken along line B—B, forillustrating the state in which the flexible magnetic disc has beenmoved towards the upper plate.

FIG. 21 is a cross-sectional view for illustrating the lower liner sheetin FIG. 19.

FIG. 22 is a cross-sectional view for illustrating the upper liner sheetin FIG. 20.

FIG. 23 is a plan view for illustrating the state in which shutteroperating arm of a disc drive device bears against the shutter member ofthe disc cartridge.

FIG. 24 is a plan view showing the state in which the shutter member ofthe disc cartridge has been opened by the shutter operating arm of adisc drive device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, preferred embodiments of according to thepresent invention will be explained in detail. The disc cartridgeaccording to the present invention is applied to a card type disc drivedevice loaded in a PC card slot in which can be mounted or dismounted aPC card of the PCMCIA (Personal Computer Memory Card InternationalAssociation) standard, such as an IC (Integrated Circuit) memory cardprovided on a notebook type personal computer, or a FAX modem card. Onthe other hand, disc drive device is adapted to the PC card slot of TYPEII (Release 2.1).

Referring to FIGS. 1 and 2, the disc cartridge 1 includes a flexiblemagnetic disc 5, and a main cartridge body unit 6 adapted forrotationally accommodating this flexible magnetic disc 5.

Referring to FIGS. 2 and 3, the flexible magnetic disc 5 is formed by asheet of e.g., polyester, to the shape of a disc having a center opening8, and has its both surfaces coated with a magnetic material. Theflexible magnetic disc 5 is formed to be e.g., of a diameter of 2 inchand to have a recording capacity of the order of approximately 150 MB(megabytes). This flexible magnetic disc 5 is rotationally driven at,for example, an rpm of 3600.

Referring to FIGS. 2 and 3, a center hub 11, adapted to rest on a disctable 9 of a disc rotating driving mechanism on the disc driving device,is mounted with an adhesive layer 12 in the center aperture 8 of theflexible magnetic disc 5. The center hub 11 is formed of a magneticmetal material and, as shown in FIGS. 2 and 3, includes a substantiallycylindrical center portion 13, adapted to rest on the disc table 9, anda flange portion 14, formed integrally with the outer periphery of thecenter portion 13 and which is adapted for being fitted on the inner rimof the center opening 8 of the flexible magnetic disc 5. The centerportion 13 of the center hub 11 is formed integrally with an engagementrecess 17 engaged by an engagement projection 16 formed on the disctable 9 of the disc drive device.

The main cartridge body unit 6 has an upper plate 21, a lower plate 22and an intermediate frame 23 sandwiched between the upper and lowerplates 21, 22, as shown in FIG. 2.

As shown in FIGS. 4 and 5, the upper and lower plates 21, 22 are formedof a metal material, such as a stainless steel material, to asubstantially square flat plate, and is of a thickness of the order of0.2 mm.

As shown in FIGS. 4 and 5, the upper and lower plates 21, 22 are formedwith substantially rectangular recording and/or reproducing apertures24, 25, at the front end sides thereof in the inserting/ejectiondirection with respect to the disc drive device, for exposing portionsof the recording area of the flexible magnetic disc 5 to outside acrossthe inner and outer rims of the disc, so that the apertures 24, 25 faceeach other. The front end sides of the upper and lower plates 21, 22 inthe inserting/ejection direction with respect to the disc drive deviceare referred to below simply as the front end sides. These recordingand/or reproducing apertures 24, 25 are formed for being opened in thefront ends of the upper and lower plates 21, 22.

Centrally of the lower plate 22 is formed a circular opening 26 forrotationally driving the flexible magnetic disc 5. The circular opening26 is adapted for permitting the disc table 9 of the disc rotatingdriving mechanism of the disc drive device to be intruded into theinterior of the main cartridge body unit 6, as shown in FIG. 5. Thisrotationally driving opening 26 has its inner diameter smaller than theouter diameter of the flange 14 of the center hub 11 of the flexiblemagnetic disc 5.

Referring to FIGS. 4 to 6, the upper and lower plates 21, 22 are formedwith substantially rectangular thickened portions 27, 28, respectively,these thickened portions including shutter sliding areas in which ashutter member 61 arranged towards the inner sides of the upper andlower plates 21, 22 as later explained is adapted for being slid andwhich is extended from the front sides towards mid portions of the upperand lower plates 21, 22.

With these thickened portions 27, 28, a sufficient gap is maintainedbetween the shutter member 61 and the inner surfaces of the upper andlower plates 21, 22, thus assuring an optimum operation of the shuttermember 61 adapted for being slid on the inner sides of the upper andlower plates 21, 22. With these thickened portions 27, 28, the upper andlower plates 21, 22 can be prevented from being flexed in the directionof thickness to improve mechanical strength.

Stated differently, the disc cartridge 1 has a thickness of its areaother than the thickened portions 27, 28 having the shutter sliding areathinner than that of the thickened portions 27, 28 to permit theflexible magnetic disc 5 to be rotated in stability.

That is, the disc cartridge 1 is rotationally driven at, for example, anrpm of 3600, higher than the rotational speed of 3000 rpm, retained tobe a higher speed, so that, under the Bernoulli's law, an air stream isproduced in a gap defined between the upper and lower plates 21, 22 andthe rotationally driven flexible magnetic disc 5, thus producing anegative pressure to maintain a balanced state between the upper andlower plates 21, 22 and the flexible magnetic disc 5.

By the flexible magnetic disc 5 being rotationally driven under thisnegative pressure state, the flexible magnetic disc 5 is maintained in aflat position without producing positional deviation or oscillations onthe recording surface. Thus, whilst it is necessary to stabilize the airstream and to maintain a constant gap between the recording surface ofthe flexible magnetic disc 5 and the inner surfaces of the upper andlower plates 21, 22, in order to stabilize the flexible magnetic disc 5rotating at an elevated speed and the air stream, higher stability maybe achieved when the gap is smaller in size. So, by the main cartridgebody unit 6 having a uniform thin thickness in areas other than thethickened portions 27, 28 having the shutter sliding area, the gapmagnitudes on the air inlet and outlet sides on both sides of themagnetic head are rendered equal to each other to permit the flexiblemagnetic disc 5 to be rotated in stability at an elevated speed.

The upper and lower plates 21, 22 are formed integrally with cut-outs29, 30, cut at an inclined angle of e.g., approximately 45° relative tothe disc inserting/ejecting direction, as shown in FIGS. 4 and 5. Bythese cut-outs 29, 30, it is possible to evade the disc cartridge 1 fromcompressing against shutter operating means provided on the disc drivedevice for acting on the shutter member 61 when the disc cartridge 1 isloaded on the disc drive device. It is noted that the other corners ofthe upper and lower plates 21, 22 are arcuate in profile.

Referring to FIGS. 4 and 5, the upper plate 21 and the lower plate 22are provided with first to fourth engagement openings 31 a to 31 d and32 a to 32 d, respectively, in the vicinity of respective cornersthereof, for being engaged in position relative to the intermediateframe 23. Referring to FIGS. 4 and 5, the first engagement openings 31 aand 32 a operate as reference openings used for positioning the upperand lower plates 21, 22 at pre-set positions on the intermediate frame23. The second engagement openings 31 b, 32 b are elliptically-shapedand serve as position adjustment holes that may be adjusted in thelong-axis direction relative to the intermediate frame 23. The third andfourth engagement openings 31 c, 31 d, 32 c, 32 d are coupling openingsfor coupling to the intermediate frame 23.

The front end side of the upper plate 21 is bent to form an abutmentpiece 34, as shown in FIG. 2. This abutment piece 34 is adapted to bearagainst the front end of the lower plate 22 when the upper plate 21 iscombined with the lower plate 22 with the intermediate frame 23in-between.

Referring to FIGS. 4 to 6, the upper plate 21 and the lower plate 22 areformed integrally with finger supports 35, 36 as thickened portionsserving as an aid for a user to hold the main cartridge body unit 6 atfinger's ends. These finger supports 35, 36 are provided close to thetrailing ends in the inserting/ejecting directions of the plates to orfrom the disc drive device. These finger supports 35, 36 are formedintegrally with plural anti-slip linear grooves for the holding fingerends, with the grooves extending parallel to the width-wise direction ofthe main cartridge body unit 6.

The intermediate frame 23 is formed as a substantially flat plate from aresin material, such as nylon6, PPS (polyphenylene sulfide) orpolycarbonate.

The intermediate frame 23 is formed to a size slightly larger than theouter size of the upper plate 21 or the lower plate 22, as shown in FIG.7. The intermediate frame 23 has a protrusion 37 along its outerperimetrical portions except its portions in register with the front endsides of the upper and lower plates 21, 22 corresponding to the shuttersliding portions. The protrusion 37is projected in a direction parallelto the major surfaces of the upper and lower plates 21, 22.

The intermediate frame 23 is formed integrally with connection recesses38, 38 on its both surfaces, as shown shaded in FIG. 7. In theseconnection recesses 38, 38 are mounted the upper plate 21 and the lowerplate 22. Referring to FIG. 4, if the outer sizes of the upper plate 21and the lower plate 22 are such that the lengths are equal and L2 andthe widths thereof are equal and W1 and W2, and the corresponding sizesof the connection recesses 38, 38 are such that the length is L2 and thewidths are W3 and W4, the relationship of L2>L1, W1>W3 and W2>W4 holds.Meanwhile, a dimensional difference α a is such that

L 2−L 1=W 1−W 3=W 2−W 4=α  (1).

The connection recess 38 is adapted for being of a depth slightly largerthan the thickness of the upper plate 21 or the lower plate 22, as shownin FIGS. 8 and 9. Therefore, the protrusion 37 of the intermediate frame23 is protruded slightly in a direction perpendicular to the majorsurfaces of the upper and lower plates 21, 22, as shown in FIG. 9.

As a result, outer peripheral edges of the upper plate 21 or the lowerplate 22, mounted within the connection recess 38, are not protrudedoutwards, so that there is no risk of the finger ends of the usertouching the protruded edges, thus assuring sufficient operationalsafety.

Referring to FIG. 9, if, in the main cartridge body unit 6 in which theupper plate 21 and the lower plate 22 are bonded within the connectionrecesses 38, 38 of the intermediate frame 23, the thickness as measuredat the protrusion 37 of the intermediate frame 23, lying at an end ofthe main cartridge body unit 6, is T1, and the thickness as measuredacross the major surfaces of the upper and lower plates 21, 22 at midportions of the main cartridge body unit 6 is T2, an amount ofprotrusion ΔT of the protrusion 37 of the intermediate frame 23 from themajor surfaces of the upper and lower plates 21, 22 is set so that thefollowing relationship

ΔT=(T 1−T 2)/2

T 1≧T 2

holds.

The bottom surface of the connection recess 38 is formed integrally withfour substantially columnar-shaped engagement projections 41 engaged inthe first to fourth engagement openings 31 a to 31 d and 32 a to 32 dformed in the upper plate 21 and in the lower plate 22, respectively.These engagement projections 41 are of such a height that, when theprojections are engaged in the first to fourth engagement openings 31 ato 31 d and 32 a to 32 d, the distal ends of the engagement projections41 are not protruded on the major surfaces of the upper and lower plates21, 22.

Referring to FIG. 4, if the first engagement openings 31 a, 32 a of theupper plate 21 and the lower plate 22 is of a diameter Φ1, the secondelliptically-shaped engagement openings 31 b, 32 b are both of diametersΦ1 and Φ2 and the third and fourth engagement openings 31 c, 31 d, 32 c,32 d are of the diameter Φ2, and the respective engagement projections41 of the intermediate frame 23 are of an outer diameter Φ3, therespective diameters are set so that Φ1>Φ3 and Φ2>Φ3. Meanwhile, adimensional difference is set so that

 Φ1−Φ3=β  (2).

In the above equations 1 and 2, the dimensional differences are set sothat α>β.

On the other hand, a dimensional difference is set so that Φ2−Φ3=2α.

By forming the first to fourth engagement openings 31 a to 31 d and 32 ato 32 d of the upper and lower plates 21, 22, and the engagementprojections 41 of the intermediate frame 23, to the aforementioneddimensions, moving the second engagement openings 31 b, 32 b, engaged bythe engagement projections 41, in a controlled fashion, with the firstengagement openings 31 a, 32 a engaged by the engagement projections 41as the reference, and by engaging the third and fourth engagementopenings 31 c, 31 d, 32 c, 32 d by the engagement projections 41, it ispossible to get the upper and lower plates 21, 22 mounted to highprecision in position in the connecting recesses 38, 38. The upper andlower plates 21, 22 are bonded and secured to the intermediate frame 23e.g., with an adhesive.

With the disc cartridge 1, in which the respective dimensions of theupper and lower plates 21, 22 and the intermediate frame 23 are set, asdescribed above, it is possible to prevent deformation, such as warping,of the upper and lower plates 21, 22, or connection troubles, becauseaccount is taken sufficiently of the effect produced due to differencein thermal expansion or contraction coefficients between the upper andlower plates 21, 22 of metal and the intermediate frame 23 of syntheticresin under high or low temperature environments.

Within the intermediate frame 23, there is defined, by cutting out ofthe resin material, a substantially circular disc housing section 45 inwhich is rotationally accommodated the flexible magnetic disc 5. Thisdisc housing section 45 is interrupted at a position in register withthe recording and/or reproducing apertures 24, 25 of the upper and lowerplates 21, 22, as shown in FIG. 7.

In the front end side of the intermediate frame 23, in register with theshutter sliding area through which slides the shutter member 61, thereare formed steps 47, 47 for shutter movement which are inserted in aspace between shutter portions 65, 65 of the shutter member 61which willbe explained substantially. The thickness of the intermediate frame 23at the steps 47 for shutter movement is selected to be thinner than thatwithin the connection recess 38.

There is formed a cut-out 49 on a front side corner of the intermediateframe 23, in register with the cut-outs 29, 30 of the upper and lowerplates 21, 22, as shown in FIG. 7. The other corners of the intermediateframe 23 are arcuate in profile, as shown.

Referring to FIG. 7, a substantially vee-shaped engagement groove 50 isformed in the intermediate frame 23 at a position adjacent to thecut-out 49 and outwardly separated from the outer periphery of the upperand lower plates 21, 22 along the width of the main cartridge body unit6. This engagement groove 50 is engaged by engagement means provided onthe disc drive device at a pre-set loading position of the disccartridge 1 when the disc cartridge is loaded on the disc drive device.

The main cartridge body unit 6 is provided with the shutter member 61,movable in the direction indicated by arrows a₁ and a₂, to enable therecording and/or reproducing apertures 24, 25 to be opened and closed,and a torsion coil spring 62, biasing the shutter member 61 in adirection of causing the shutter member 61 to close the recording and/orreproducing apertures 24, 25, as shown in FIGS. 10 to 12.

The shutter member 61 is formed of a relatively rigid metal material,and is of a substantially U-shaped cross-section, having a pair ofparallel shutter portions 65, 65 facing each other, and a web 66interconnecting the proximal ends of the shutter portions 65, 65, asshown in FIGS. 10 to 12. Meanwhile, the facing gap on the distal endsides of the shutter portions 65, 65 of the shutter member 61 isselected to be slightly larger than that at the proximal end. Since theshutter portions 65, 65 are substantially chevron-shaped, the distalends of the shutter portions 65, 65 are prevented from compressingagainst the recording area of the flexible magnetic disc 5. Thethickness of the shutter portions 65, 65 is selected to be approximately0.15 mm.

Referring to FIGS. 12 to 15, the substantially rectangular apertures 68,68 slightly larger than the recording and/or reproducing apertures 24,25 are formed at registering positions to each other in the shutterportions 65, 65, with the apertures 68, 68 extending across theconnecting web portion 66. That is, the respective apertures 68 of theshutter member 61 are opened towards the connecting web portion 66 ofthe shutter member 61. A magnetic head, not shown, of the disc drivedevice is moved parallel to the recording surface of the flexiblemagnetic disc 5 so as to be intruded into the recording and/orreproducing apertures 24, 25 from the opening side of the connecting webportion 66.

The shutter portions 65, 65 of the shutter member 61 are formed on bothsides in the movement direction of the shutter portions 65, 65integrally with first and second guide projections 71, 71, 72, 72,adjacent to the connecting web portion 66, these guide projections beingmovingly engaged with the upper and lower plates 21, 22, as shown inFIGS. 10 and 11. Since these first and second guide projections 71, 71,72, 72 are formed by e.g., press working, so that portions 65, 65 willbe protruded outwards, as shown in FIGS. 16 and 17, the distal ends ofthe guide projections 71, 71, 72, 72 are not sharp, thus assuring safetyin case the user's finger end touches these distal ends.

Referring to FIGS. 16 and 17, the first guide projections 71, 71 areformed towards the connecting web portion 66 integrally with firstlimiting surfaces 75 for extending substantially at right angles to themajor surface of the shutter portions 65, 65. These first guideprojections 71, 71 are engaged by the upper and lower plates 21, 22 toprevent the shutter member 61 from being disengaged by moving in thedirection indicated by arrow b₁ in FIG. 16, that is towards the outerrim of the flexible magnetic disc 5. Referring further to FIGS. 16 and17, the second guide projections 72, 72 are formed towards the distalends of the shutter portions 65, 65 integrally with second limitingsurfaces 76 for extending substantially at right angles to the majorsurface of the shutter portions 65, 65. These second guide projections72, 72 are engaged by the upper and lower plates 21, 22 to prevent theshutter member 61 from being disengaged by moving in the directionindicated by arrow b₂ in FIG. 16, that is towards the inner rim of theflexible magnetic disc 5. As shown in FIGS. 16 and 17, these first andsecond guide projections 71, 71, 72, 72 are provided at facing positionsof the shutter portions 65, 65 on both sides of the apertures 68 of theshutter portions 65.

So, the shutter member 61 is prevented from being detached towards anouter side and towards the center of the main cartridge body unit 6 bythe first and second guide projections 71, 71, 72, 72.

The guide projections 71, 72 lying on both sides of the aperture 68 ofone of the shutter portions 65, 65 and the guide projections 71, 72lying on both sides of the aperture 68 of the other shutter portion 65are offset in their positions in a direction perpendicular to the movingdirection of the shutter portions 65, 65, as shown in FIGS. 10 and 11.

On both sides of the recording and/or reproducing apertures 24, 25 inthe thickened portions 27, 28 of the upper and lower plates 21, 22,linear guide slits 78, 78, 79, 79 are provided for extending along thefront sides of the upper and lower plates 21, 22, as shown in FIGS. 4and 5. Into these guide slits 78, 78, 79, 79 are movingly intruded thefirst and second guide projections 71, 71, 72, 72 of the shutter member61.

The first and second guide projections 71, 72, intruded into these guideslits 78, 79, are flush with or slightly receded from the major surfacesof the upper and lower plates 21, 22, as shown in FIGS. 16 and 17. Thatis, the first and second guide projections 71, 72 are formed so that thedistal ends thereof are not protruded outwards from the guide slits 78,79, to assure safety of the finger end handling the disc cartridge 61.

The guide slits 78, 79 and the guide slits 78, 79 lying on both sides ofthe recording and/or reproducing apertures 24, 25 are provided atrelatively offset positions in a direction perpendicular to thedirection of movement of the shutter portions 65, 65.

The shutter member 61 is arranged so that the respective shutterportions 65, 65 are arranged between the inner surfaces of the upper andlower plates 21, 22 and the intermediate frame 23, and so that, by thefirst and second guide projections 71, 71, 72, 72 being introduced intothe guide slits 78, 78, 79, 79 from the inner surfaces of the upper andlower plates 21, 22, the respective shutter portions 65, 65 are slidablelinearly in the direction indicated by arrows a₁ and a₂ through theinside of the main cartridge body unit 6, as shown in FIGS. 16 and 17.

In the connecting web portion 66 of the shutter member 61 is formed anactuating portion 81, adjacent to the aperture 68 towards an end thereofin the moving direction of the shutter member 61, by segmenting aportion of the connecting web portion 66 and the portions of the shutterportions 65, 65 contiguous thereto, as shown in FIGS. 10 and 11. Theactuating portion 81 is configured for being acted on by shutteroperating means, not shown, provided on the disc drive device. Thisactuating portion 81 is formed integrally with an abutment piece, notshown, abutted on by the shutter operating means. The actuating portion81 is formed at its one end in the moving direction of the shuttermember 61 by folding a portion of the connecting web portion 66.

In the forward end sides of the upper and lower plates 21, 22 are formedcut-outs 83, 84 for moving the actuating portion 81 of the shuttermember 61, as shown in FIGS. 4 and 5. From ends of the cut-outs 83, 84are extended inclined guide portions 85, 86, continuing to the outerperiphery, for guiding the shutter operating means provided on the discdrive device into the inside of the cut-outs 83, 84, as shown in FIGS. 4and 5. In the forward end side of the intermediate frame 23,there isformed an operating cut-out 87 for moving the actuating portion 81 ofthe shutter member 61, in register with the cut-outs 83, 84 in the upperand lower plates 21, 22, as shown in FIG. 7. From an end of the cut-out87 is extended an inclined guide portion 88, continuing to the outerperiphery, for guiding the shutter operating means provided on the discdrive device into the inside of the cut-out 87, as shown in FIG. 7. Theconnecting web portion 66 of the shutter member 61 is formed integrallywith a spring retainer 90 at its one end in the direction indicated byarrow a₂, as shown in FIGS. 2, 10 and 11. The spring retainer 90 isengaged by an end of the torsion coil spring 62.

The torsion coil spring 62 is provided at a forward corner of the maincartridge body unit 6, as shown in FIG. 2. The intermediate frame 23 isformed with a cut-out 92 in which to accommodate the torsion coil spring62, as shown in FIG. 7. The inner peripheral surface of the cut-out 92for mounting the spring therein is formed integrally with an engagementsurface 93 engaged by the opposite end of the torsion coil spring 62.The torsion coil spring 62 has its one held by the spring retainer 90 ofthe shutter member 61, while having its opposite end engaged by anengagement surface 93 of the cut-out 92 of the intermediate frame 23 inwhich to accommodate the torsion coil spring 62.

So, the shutter member 61 is biased in the direction indicated by arrowa₁ under the spring force of the torsion coil spring 62, so that theshutter member 61 has been moved to a positionin which the apertures 68,68 of the shutter portions 65, 65 are not in register with the recordingand/or reproducing apertures 24, 25 of the upper and lower plates 21,22, thus closing the recording and/or reproducing apertures 24, 25, asshown in FIGS. 10 to 12. On the other hand, the shutter member 61 ismoved in the direction indicated by arrow a₂, against the force of thetorsion coil spring 62, so that the shutter member 61 is moved to aposition in which the apertures 68, 68 of the shutter portions 65, 65are in register with the recording and/or reproducing apertures 24, 25of the upper and lower plates 21, 22, thus opening the recording and/orreproducing apertures 24, 25, as shown in FIGS. 13 to 15.

The main cartridge body unit 6 is provided with an upper liner sheet 101and a lower liner sheet 102, adapted for protecting the recordingsurface of the flexible magnetic disc 5, as shown in FIGS. 2, 21 and 22.The upper and lower liner sheets 101, 102 are each comprised of anon-woven cloth layer 104 and a film-shaped laminated layer of resin105, and are each formed as a disc of substantially the same diameter asthe outer diameter of the flexible magnetic disc 5, as shown in FIGS. 21and 22.

The upper and lower liner sheets 101, 102 is formed with a substantiallyrectangular first cut-out 107, roughly in register with the shutterslide area for the shutter member 61, shown by cross-hatching, and asubstantially circular second center cut-out 108, larger in diameterthan the rotationally driving opening 26 in the lower plate 22, andwhich is contiguous to the first cut-out 107, as shown in FIG. 18. Theseupper and lower liner sheets 101, 102 are bonded in position, as theupper and lower liner sheets 101, 102 are deformed along the thickenedportions 27, 28, by setting a laminated layer 105 on the inner surfacesof the upper and lower plates 21, 22 and by welding the laminated layer105 to the inner surfaces o the upper and lower plates 21, 22.

During handling, the flexible magnetic disc 5 of the disc cartridge 1 ismoved in a direction of approaching to the lower plate 22, so that theflange 14 of the center hub 11 rests on the inner surface of the lowerplate 22, as shown in FIG. 19. Alternatively, the flexible magnetic disc5 of the disc cartridge 1 is moved in a direction of approaching to theupper plate 21, so that the mid portion 13 of the center hub 11compresses against the inner surface of the upper plate 21, as shown inFIG. 20.

The lower liner sheet 102 is of a pre-set thickness, such that, with theflexible magnetic disc 5 moved towards the lower plate 22, at least asmall gap G persists between the flexible magnetic disc 5 approaching tothe lower liner sheet 102 and the lower liner sheet 102, as shown inFIGS. 19 and 21. Thus, the flexible magnetic disc 5, approaching to thelower plate 22, is positively prohibited from damaging the recordingsurface by being deformed upwards by an edge of the lower plate 22deformed along the thickened portion 28 of the lower plate 22, as shownin FIG. 21.

The upper liner sheet 101 is similarly of a pre-set thickness, suchthat, with the flexible magnetic disc 5 moved towards the upper plate21, at least a small gap G persists between the flexible magnetic disc 5approaching to the upper liner sheet 101 and the upper liner sheet 101,as shown in FIGS. 20 and 22. Thus, the flexible magnetic disc 5,approaching to the upper plate 21, is positively prohibited fromdamaging the recording surface by being deformed upwards by an edge ofthe upper plate 21 deformed along the thickened portion 27 of the upperplate 21, as shown in FIG. 22.

Although not shown, the upper and lower liner sheets 101, 102 are eachprovided with a non-woven cloth layer 104 and a laminated layer of resin105. For example, the upper and lower liner sheets 101, 102 may becomprised of a lubricious sheet, such as an ultra-high-molecularpolyethylene-, fluorine- or Teflon sheet, provided with an adhesivelayer. This lubricious sheet is bonded to the inner surfaces of theupper and lower plates 21, 22 via adhesive layers.

With the upper and lower liner sheets 101, 102 having the lubricioussheets, the thickness of the sheets can be diminished as compared tothat of the sheet having the non-woven cloth layer 104 and thefilm-shaped laminated layer of resin 105. Thus, a sufficient gap may bemaintained between the flexible magnetic disc and the upper and lowerliner sheets 101, 102, whilst the thickness of the main cartridge bodyunit can be reduced further.

The disc drive device, in which is loaded the above-described disccartridge 1, as described above, includes a cartridge loading unit 201in which to load the disc cartridge 1, and a shutter operating arm 202for opening the shutter member 61 of the inserted disc cartridge 1, asshown in FIG. 23. The shutter operating arm 202 is provided at a forwardside corner of the disc cartridge 1 to be inserted in the disc drivedevice so that the shutter operating arm 202 is rotatable via a rotarypivot 203 in the direction indicated by arrows c₁ and c₂.

The disc drive device is also provided at a pre-set position in thecartridge loading unit 201 with a lock arm 205 by a rotary pivot 206 forrotation in the direction indicated by arrows dl and d2. The lock arm205 is adapted for locking the intruded disc cartridge in position. Thedisc drive device is also provided in the cartridge loading unit 201with positioning pieces 208, 209 facing both lateral surfaces runningparallel to the inserting/ejecting directions of the disc cartridge 1,as shown in FIG. 23.

The operation of loading the above-described disc cartridge 1 in thedisc drive device to record and/or reproduce the information on or fromthe flexible magnetic disc 5 is hereinafter explained with reference tothe drawings. When intruded into the inside of the disc drive device,the disc cartridge 1 has its intruding direction restricted by abutmentagainst a positioning piece 208, as shown in FIG. 23. Simultaneously,the digital end of a shutter actuating arm 202 compresses against theactuating portion 81 of the shutter member 61.

As the disc cartridge 1 is loaded on the cartridge loading unit 201 ofthe disc drive device, the shutter actuating arm 202 is rotated in thedirection indicated by arrow c₂ in FIG. 24 to cause movement of theshutter member 61 in the direction indicated by arrow a₂ to open therecording and/or reproducing apertures 24, 25, as shown in FIG. 24. Whenthe disc cartridge 1 is loaded on the cartridge loading unit 201, thepositioning pieces 208, 209 compress against the lateral sides in theinserting/ejecting direction, at the same time as the lock arm 205 isrotated in the direction indicated by arrow d2, such that the lock arm205 has its distal end engaged in the engagement groove 50 on thelateral sides of the main cartridge body unit 6, as shown in FIG. 24.The disc cartridge is pulled to a pre-set loading position in thecartridge loading unit 201 by the lock arm 205 engaged in the engagementgroove 50, so as to be locked in position, as shown in FIG. 24.

With the disc cartridge 1, the flexible magnetic disc 5 set on the disctable 9 is run in rotation, whilst the magnetic head is intruded intothe recording and/or reproducing apertures 24, 25 from the apertures 68,68 in the shutter member 61 to record and/or reproduce the informationon or from the flexible magnetic disc 5.

With the above-described disc cartridge, comprised of the main cartridgebody unit, made up of the upper and lower plates 21, 22 formed of ametal material and the intermediate frame 23 bonded in position betweenthe upper and lower plates 21, 22, the upper plate 21 can be easilyconnected to the lower plate 22. With this disc cartridge 1, the maincartridge body unit 6 can be reduced in size and thickness withoutdeteriorating the appearance or structural integrity of the maincartridge body unit 6.

Moreover, with the disc cartridge 1, in which the upper plate 21 and thelower plate 22 are provided on the major surface of the main cartridgebody unit 6, it is possible to suppress the powder debris produced onabrasion of the metallic upper and lower plates 21, 22, so that adverseeffects ascribable to powder debris can be inhibited to improvereliability in the recording and/or reproducing operation.

Also, in the disc cartridge 1, the portions of the main cartridge bodyunit 6 other than the thickened portions 27, 28 are formed to a uniformthin thickness to render it possible to stabilize the rotationaloperation of the flexible magnetic disc 5.

In addition, in the disc cartridge 1, in which the intermediate frame 23is formed of a resin material, the intermediate frame 23 can be bondedeasily to the upper plate 21 and the lower plate 22 to improve theassembling performance. In the present disc cartridge, the protrusion 37of the intermediate frame 23 is provided on the outer rim of the maincartridge body unit 6 so that there is no risk of edges of the upper andlower plates 21, 22 projecting from the intermediate frame 23 of resin,thus assuring sufficient safety in handling.

The disc cartridge 1 has the shutter member 61 sliding linearly withinthe inside of the main cartridge body unit 6, whereby the supportingstructure for the shutter member 61 can be simplified. Moreover, whenthe disc cartridge is intruded into or ejected from the disc drivedevice, the shutter member 61 may be prevented from compressing againstthe cartridge inserting/ejecting opening provided on the disc drivedevice, whilst the shutter member 61 may be reliably prohibited fromsliding against a door rotatably mounted on the cartridgeinserting/ejecting opening. Thus, with the present disc cartridge 1, itis possible to prevent the shutter member 61 from being destructed aswell as to improve operability in inserting/ejecting the disc cartridge1 to or from the disc drive device.

Although the disc cartridges 1, 2 according to the present invention areconfigured for housing the flexible magnetic disc 5 therein as adisc-shaped recording medium, it is to be noted that the disc-shapedrecording medium may be of other types, such as a magneto-optical disc.

What is claimed is:
 1. A disc cartridge comprising: a disc-shapedrecording medium; a main cartridge body unit including an upper plateand lower plate, both of a metal material, forming a plate pair, and anintermediate frame, sandwiched between the upper and lower plates, saidmain cartridge body unit housing said disc-shaped recording mediumtherein; a recording and/or reproducing aperture formed in said maincartridge body unit for exposing a portion of a recording area of saiddisc-shaped recording medium to outside across the inner and outer rimsthereof; and a shutter member provided for linear movement within theinside of said main cartridge body unit for opening/closing saidrecording and/or reproducing aperture whereby said shutter memberincludes a plurality of guide projections which are movingly engagedwith said upper and lower plates.
 2. The disc cartridge according toclaim 1 wherein a movement area in which said shutter member is moved isformed by being swollen out on the major surface(s) of said upper plateand/or the lower plate.
 3. The disc cartridge according to claim 1wherein said shutter member has an operating portion moved by beingabutted on by shutter actuating means provided on a recording and/orreproducing apparatus.
 4. The disc cartridge according to claim 1wherein an elastic member for biasing said shutter member in a directionof closing said recording and/or reproducing aperture is provided onsaid main cartridge body unit and wherein said shutter member isprovided with an engagement portion engaged by said elastic member. 5.The disc cartridge according to claim 1 wherein a plurality of saidrecording and/or reproducing apertures are provided in said maincartridge body unit for facing each other; said shutter member has apair of shutter portions facing each other for opening/closing saidrecording and/or reproducing apertures and a connecting web portioninterconnecting proximal portions of said shutter portions; a gapbetween said facing shutter portions being larger in the distal portionsthan in the proximal portions thereof.
 6. The disc cartridge accordingto claim 5 wherein said shutter portions of said shutter member areprovided with apertures for opening said recording and/or reproducingaperture.
 7. The disc cartridge according to claim 6 wherein saidrecording and/or reproducing apertures are opened in one end of saidmain cartridge body unit and wherein the apertures in said shuttermember are opened towards the connecting web portion.